Felicia Was Always a Good Student,earning Mostly B's in High-School

Felicia was always a good student,earning mostly B's in high-school.When she arrived at university,she was paired with Amelia,a straight-A student.Over the semester,Felicia and Amelia spent a lot of time together studying,talking,and hanging out.At the end of the term,Felicia noticed that most of her grades had started improving.Felicia's academic success might be attributed to

A) social resilience.
B) coercion.
C) set point changes.
D) social contagion.